Butch,when you get the chance,check your casting nmbers,and clutch pivot ball mounting hole.if there are 2 such holes,one farther forward,and the oil filter adapter looks different from a normal small block,you may have a VERY rare and valuable block there.My 66 nova came thru with the 350 hp 327,and had those features,and I was told they went into some Vettes as well.I do know that the "L-79"[350hp-327] was availeable in 67 as well.best of luck here,Butch.